Improvements in automatic guns having a detachable barrel



mm, mm@ www@ wm m n hwmw .Il mmm TB9 DmEl ROL QN Awww Amy .INA1. Axmu i. iii ii. MsJ N v Bmw A @@Nhw L@ Nm l m m Nm@ N D E mv J n Mm I ha m ATTUHNEY .miPRovEMENrs INAUTOMATIQGUNS HAVING A DETACHABLE BARREL Bernard IMaillard, Geneva, Swit'aerlaiid, ss'ign'or 4to States iPatetrt t 'Brevets Aero-Mecaniques S. A., Geneva, Switzerland,

fa Swiss society Application .July zaisszt'serii No. 445,099

' Claims priority,-applicationLuxemburgiduly @27, 195B 4fcla'ims. (c1.s`9"193) 'The'.present linvention relates tobutomatic guns having a detachably secured barrel and -including vin the breech case 'a mechanism controlled by {gases tapped from said-barrel.

The Ychief object of my invent-ion is to'provi'de a-.gun of this "type which is 'better adapted `to meet the r-lrequifrements of practice, in particular concerning the'transmission vof the gases `tapped from the barrel to the vmechanism providedin the breech case.

There are known guns of this type in -which lthe gases are conveyed from the barrel 4to themechanis'm through conduits carried :by the barrel and opening into -a su'rf ace of said barrel which lits, when the'barrel is fixed to the breech case, against `a corresponding surface -from which start-corresponding conduits le'adingtosaid ymechanism. 'ff he V-drawbac-klo'f this arrangementisthat the :two abovementioned cooperating surfaces get jammed against each other due to the unavoidable presence f'of impurities inthe powderfgases vtapped from the -gun barrel.

According to `-my invention, vthe gun barrel carries yat least one cylinder preferably ,parallel to the barrel axis and towhich the igases are fed from the boreof said barrel, this cylinder opening oppositeone-:end Ywall-of a cylindrical housing carried by thebreech case, whichiend wall is .provided with a :hole for -feeding yta'ppedgfpowder gases -to the -mechanismto be operated l'by-sa-i'd gases, a pistomprovided -withfa small 'flongitudinalpassage extending therethrough being lsli'dable in said cylinder, `so `that when ashot is tred, the I.powder l'gases -'apply said piston in .a gastight vmanner =against said housing -end wall tand a portion of said gases pass throughsaid .longitudinalpassage into said housing toopera-te theabove Imentioned mechanism.

A preferred embodiment of my -invention vw'illbe'hereinafter described with reference to the accompanying drawings given merely by way of example and in which:

Fig. l is -a--seetional vviewtanthe lline fImI'o'f '1Fig. 3 of a gun made accordingto-myfinvention.

Fig. 2 is a sectional view on the linefIIflII of Fig. 3.

fFi'gS is 'a cross sectional view'bh-ithe-line I='III'of Fig. f

fy lirive'r'ition will be describedas applied to anatit matic g'un *(ffor instance -of acalibF-rahging from 20 'to 50 mm.) including, to keep its breech-block temporarily in locked position, a movable system controlled, every time a shot is fired, by powder gases tapped from the barrel of the gun.

In the construction illustrated by the drawings, the gun includes a barrel 1 fixed at the rear thereof in a detachable manner to a breech case 2 in which is slidable a breech-block 3 adapted to reciprocate in a direction parallel to the axis of the barrel.

Breech-block 3 is provided with a locking member 4 adapted to bear, once said breech-block has reached its front position, against an abutment piece 5 rigid with breech case 2.

In order to hold locking member 4 in position, there are provided two sliding side bars 6 disposed on either 2,818,785 Patented Jan. 7, 19 58 ICC 2 side of breech-block 3 vand arranged to bring-member "4 into active position and then to hold it in said lposition during Ithe-complementary forward movement performed by said sliding members 6 after the breech-block 3 has reached its front end position.

The whole of breech-block 3 and sliding bars "6 iis subjected to the action of a recuperator spring 7 `bearing against a cross piece 8 Iextending between said "sliding bars and passing 'throughbreechhblock 3provided for this purpose with an elongated slot 9, said .piece 8 acting as support for the firing pin 10 'of thegun.

Sliding bars 6 are Vsubjected to the `actionof twosprings 29. It is under the combined actionsof springs `7 and-.29 that the sliding bams perform their supplementary frontward displacement during lwhich the Amember 4 is :held in active position and the shot is iired bythe firing .pin.v

Barrel 1Vis detachably fixed to breech case `2 by means of screw-threads 11 formed in the rearportion 12'of `the barrel engaged in a cylindrical sleeve 13 provided at "the frontof the breech case.

Barrel 1gis vprovided with a tap hole '14 opening under a `jacket 15 which surrounds the barrel ahead of tfhefportion Y12 thereof, this jacket having its rea-r edge at :16.

I provide in the rear portion of jacket 15, two cylindrical bores 17 having their axes 'parallel to the `barrel axis and opening rearwardly-in edge 16, thesebores having 'for instance a diameter 'averaging 8 mm. 4for a barrel of a caliber of 20 mm., and b'eing'of a length of about 30mm.

In order to convey the powder gases yfrom tap 'hole l14 to bores 17, the outer wall of the tube is Lprovided with at least one groove extending rearwardly as far as 4the transverse plane of the 4front 'ends of bores 17'and; jacket 15 -is provided with passages connecting the 'rea'r'endof said :groove `with .the front -ends of cylindrical bores 17. For this purpose, the inner surface of jacket 15 maybe milled at 18 so as yto provide a connection between'the inner` surfaceof said jacket yand the insideof lbores 717.

yAdvantageously, as shown by the idrawihg, there :is :a singlegroove 119 extendingalong a Igeneratrix of theoute'r surface .of thebarrel and'startinglfrom tap hole 14 i-nthe rearward direction tothe vicinity v:of the front end fof zone 12. A From.apoint-of-,this -groove 19 ahead'fofthe rear end thereof start two :'othergrooves 20 `directed A:in such manner thattheyllead topoints connectedfthr'ou'gh passages 18 with th e front-endsofbores 17. Thusrthe p ortionof groove `lillt'fcated :rearward of Ythe point from whichbranchgrooves 42 0 constitutes -a-kind of-deadiend in which ,accumulate the Aimpurities contained -in tthe powder gases, whereby said gases are puriedbeforet'beirtgledtobores1f7. v j" '-In each Ofsaid `cylindricalboresL17,Iprovide'atsniallpiston `2"1 sliding with asnugtlt-herein and y provided with,

'-Advantageously, cylinders 4Cl-7 arefd-isposed soth'at their.

. respective axes ar'e located .symmetrically withfrespeottto the vertical plane of symmetry of the gun andfaire-inline with\thennlockingpush@pieceswhichhwillnowbe retenied to.

The front portion of breech case 2 is provided with two bores or cylindrical housings 23 disposed in such manner that When the barrel and the breech case are assembled together, these Icylindrical housings 23, which open toward the front, are respectively :coaxial with the cylinders 17 of jacket 15.

Each of these cylinders 23 is closed at the front end thereof by a plug 24 provided with an axial passage 25.

The rear edges of cylinders 17 are not tightly applied against plugs 24. A piston 26 is slidable in cylindrical housing 23.

A push-piece 27 (already above referred to) is mounted 3 in the portion of the breech case at the rear of cylindrical housings 23 and this push-piece cooperates through its front end with piston 26 and through its rear end with the front edge of the correspon-ding'sli'din'g bar 6.V

This system works in the following manner.

.Once a shot has been red and as soon as the shell has moved in the barrel bore ahead of tap hole 14, powder gases escape through the said hole and pass through grooves 19 and 20 into cylinders 17. Y.

These gases acting upon pistons 21 push said pistons rearwardly, thus strongly applying the rear faces of said pistons against the front faces of plugs 24. If these corresponding surfaces are suitably machined, the high pressure exerted by the gases achieves a good gas-tightness in the zone of contact between said surfaces.

A portion of the gases ows through passages 22 and 25 so as to act upon pistons Z6 which are then pushed rearwardly and compel push-pieces 27 to move back, thus driving sliding bars 6 rearwardly.

The breech-block is then released and can therefore reciprocate. When it comes back to its front end position, the sliding bars have a complementary forward stroke as above described and act upon the rear ends of push-pieces 27, which are thrown frontwardly. The elements of the breech mechanism are then back in their initial positions and the same cycle again takes place due to the fact that when the sliding bars reach their front end position a new shot is being red. l

Advantageously, means are provided to prevent, during the taking to pieces of the gun, pistons 21 and possibly plugs 24, from dropping from their respective housings. Concerning pistons 21, such means must of :course enable the pistons to have the slight axial displacement that is necessary to apply them against plugs 24. Said means may simply consist of a split ring 28 tending to expand outwardly, inserted in a peripheral groove of each piston and elastically applied against the inner wall of cylinder 17.

With the arrangement above described, when the barrel is being detached from the breech case, as pistons 21 are not tightly held against plugs 24, any clogging that might be produced by the impurities between these two elements is avoided and there will be no diticulty in detaching the barrel from thebreech case.

Of course, the rate of tire of the gun will depend upon the cross section of passages 22.

It is possible, by changing pistons 21, to vary the rate of re of the gun and to `give it the desired value.

On the contrary, the section of passages 25 will have no influence upon the rate of re if`these passages are of a cross section or area substantially greater than that of passages 22. Y

In a general manner, while I have, in the above'description, disclosed what I deem to be practical and ecient embodiments of my invention, it should be well understood that I do not wish to be limited thereto as there might be changes made in the arrangement, disposition and form of the parts without departing from the principle of the present invention as comprehendedwithin the scope of the accompanying claims.

What I claim is:

1. An automatic gun which-comprises, in combination,

a breech case, a barrel detachably fixed to said breech case, said breech case being provided with at least one cylindrical housing for receiving gases tapped from said barrel, one end wall of said housing being provided with a passage extending therethrough, a cylinder carried by said barrel having one end thereof located opposite the outer face of said housing end wall when said barrel is fixed on said breech case, said barrel being provided with at least one tap conduit connecting the bore thereof with the other end of said cylinder, and a piston in said cylinder provided with a longitudinal passage extending therethrough, this passage being in line with said first mentioned passage', the outer end of said piston being shaped to t against the outer` face of said housing end wall when the powder gases escaping from the bore of said barrel through said tap vconduit push said piston against said end wall, whereby said two passages are connected together end to end with a gas-tight t when said gases are to flow therethrough.

2. An automatic gun which comprises, in combination, a breech case, a barrel detachably xed to said breech case, said breech case being provided with at least one cylindrical housing parallel to said barrel for receiving gases tapped from saidA barrel, the front end wall of said housing being provided with a passage extending therethrough, a :cylinder parallel to said barrel and icarried by it having the rear endthereof located opposite the outer face of said housing front end wall when said barrel is xed on said breech case, said barrel being provided with at least one tap conduit connecting the bore thereof With the front end of said cylinder, and a piston in said cylinder provided with a longitudinal passage extending therethrough, this passage being in line with said rst mentioned passage, the outer end of said piston projecting rearwardly from lsaid cylinder and being shaped to t against the outer face of said housing front end wall when the powder gases escaping from the bore of said barrel through said tap conduit push said piston against said end Wall, whereby said two passages are connected together end to end with a gas-tight lit when said gases are to tlow therethrough.

3. Av gun according to claim 2 in which said tap conduit includes, in said barrel, a longitudinal groove and an oblique groove extending between the front end of said cylinder and a point of said longitudinal groove ahead of the rear end thereof, said gun including a sleeve surrounding the yportion of said barrel including said grooves so as to close them.

4. A gun according to claim 2 further including means for preventing said piston from dropping from said cylinder Whilefleaving it free to move to a limited degree therein.

References .Cited in the le of this patent UNITED` STATES PATENTS Maillard Dec. 4, 1951 

